This invention relates to load carrying vehicle platforms and particularly to the suspension therefor, it being a general object of this invention to elevate the platform from ground level to operational height from ground level and vice versa. It is a wheeled vehicle with which this invention is concerned, and as disclosed herein a most practical application is to a trailer for transporting motorcycles or "Bikes" and the like. However, it is to be understood that the suspension disclosed herein is applicable to other types of vehicles and has the advantage of lowering the load carrying platform thereof to ground level, in order to facilitiate loading and unloading.
Heretofore, vehicles such as wheeled trailers have been constructed with a fixed ground clearance. That is, the load carrying platforms are usually positioned fixed distance above ground or roadway level, and which requires lifting the load to and from the platform level. In the case of loading motorcycles or bikes, a six to twelve inch lift, is a difficult task. And for example, a usual heavy bike trailer will accomodate three such bikes. Therefore, and in order to facilitate loading and unloading of heavy bikes, it is an object of this invention to alternately raise and lower the vehicle or trailer platform to an from ground or pavement level. It is also an object to raise and lower the vehicle or trailer platform whether or not it is connected to a traction or towing vehicle. And, the height to which the platform is to be raised can vary as may be required, a low riding trailer being shown and described herein.
Vehicle suspensions can be unsprung or sprung, the former being the type employed herein, since motorcycles or bikes have sophisticated suspension systems that damp the shock forces transmitted from the pavement to the mass of the bikes carried on the trailer platform. However, it is an object of this invention to provide a trailer platform that is transversely flexible and sufficiently resilient to have a semi-sprung effect. Accordingly, the platform is characterized by a flexible perimeter frame that supports a transversely flexible and resilient platform. As will be described, this elevating suspension is comprised of a rigid lever system at each supporting wheel of the trailer.
The platform elevating vehicle suspension is comprised of separate right and left hand wheel suspension units, it being an object of this invention to provide a lever system having mechanical advantage to lift and lower the weight of at least three heavy bikes. In practice, the leverage employed is at least six to one, and this can be increased commensurate with the length of the power arm of the lever system, a first class lever being employed. An object and feature of this lever system is to provide infinite mechanical advantage at one end of the lever motion, by employing the toggle principle of operation, and whereby any displacement from the other end of lever motion increases the mechancial advantage commensurate with said displacement.
It is an object of this invention to provide lock means for releasably securing the lever system in a raised condition, and in which condition the lever system has maximized leverage for gentle release from said locked condition. it is also an object of this invention to provide an elevating vehicle syspension that is compact and reliable in its operation .